Imagine a door that locks when you pinch the knob. Crazy, right?

Imagine a door that locks when you pinch the knob. Or a smartphone that can be silenced by a hand gesture. Or a chair that adjusts room lighting when you recline into it.

A team of researchers at Disney Research and Carnegie Mellon University in Pittsburgh have come up with a system called Touché, which uses the same capacitive technology as a smartphone's touchscreen to imbue everyday objects with body and gesture recognition.

Your smartphone works thanks to capacitive coupling. The screen's surface is coated with a transparent conductor that carries an electrical signal, and that signal is redirected when a finger is touching the screen. The phone monitors the change in signal and can determine where a touch occurs.

This is typically a binary configuration, as the screen is either being touched or it isn't. Instead, the team at Disney measures across a wide range of signal frequencies to derive more information. This means that each gesture—a tap, a pinch, a grasp, a flat palm—has a different multi-frequency "capacitive profile" to be recognized.

Plus, different body tissues have different capacitive properties, so monitoring a range of frequencies can also detect a number of different paths that the electrical charge takes through the body.

It's called Swept Frequency Capacitive Sensing (SFCS), and while it means analyzing hundreds of data points at any time, modern microprocessors are now fast enough to handle the data load.

Some of the proof-of-concept applications in the lab include a smart doorknob that knows whether it has been grasped, touched, or pinched; a chair that dims the lights when you recline into it; a table that knows if you're resting one hand, two hands, or your elbows on it; and a tablet that can be pinched from back to front to open an on-screen menu.

The technology can also be shoved in wristbands, so you can make sign-language-style gestures to control the phone in your pocket—two fingers on your palm to change a song, say, or a clap to stop the music. It can also go in liquids, to detect when fingers and hands are submerged in water.

"In our laboratory experiments, Touché demonstrated recognition rates approaching 100 percent," claims Ivan Poupyrev, senior research scientist at Disney Research in Pittsburgh. "That suggests it could immediately be used to create new and exciting ways for people to interact with objects and the world at large."

Chris Harrison, from Carnegie Mellon's Human-Computer Interaction Institute says, "devices keep getting smaller and increasingly are embedded throughout the environment, which has made it necessary for us to find ways to control or interact with them, and that is where Touché could really shine."